FPGA platforms have been widely used in many modern digital applications due to their low prototyping cost, short time-to-market and flexibility. Field-programmability of FPGA bitstream has made it as a flexible and easy-to-use platform. However, access to bitstream degraded the security of FPGA IPs because there is no efficient method to authenticate the originality of bitstream by the FPGA programmer. The issue of secure transmission of configuration information to the FPGAs is of paramount importance to both users and IP providers. In this paper we presented a "Self Authentication" methodology in which the originality of sub-components in bitstream is authenticated in parallel with the intrinsic operation of the design. In the case of discovering violation, the normal data flow is obfuscated and the circuit would be locked. Experimental results show that this methodology considerably improves the IP security against malicious updates with reasonable overheads.